The long-term objective is to advance the methodology currently available for examination of the structure and function of inhibitory GABA containing nerve endings in the mammalian central nervous system; more specifically to delineate the structural requirements for neuronal uptake inhibition and release of GABA, to develop selective electron microscopical visualizing agents for GABA-ergic structures, to resolve the question of vesicular storage and release of GABA by development of truly physiological methods for examination of the vesicular uptake mechanisms, and to improve current methodology for the isolation of synaptosomes enriched in GABA-containing structures.